Table 2.
AAT MM versus MZ Subjects with COPD in the LTRC Study
| Characteristic | MM | MZ | P |
|---|---|---|---|
| n | 536 | 25 | — |
| Age, yr, mean (SD) | 65.14 (9.54) | 60.56 (7.41) | 0.018 |
| Non-Hispanic White, n (%) | 486 (90.7) | 24 (96.0) | 0.582 |
| Sex, F, n (%) | 239 (44.6) | 13 (52.0) | 0.601 |
| Current smoker, n (%) | 41 (8.1) | 1 (4.2) | 0.754 |
| Smoking pack-years, mean (SD) | 47.25 (33.18) | 36.70 (23.23) | 0.124 |
| Prebronchodilator FEV1% predicted, mean (SD) | 54.05 (25.01) | 38.09 (22.98) | 0.002 |
| Prebronchodilator FEV1/FVC, mean (SD) | 0.51 (0.14) | 0.40 (0.17) | <0.001 |
| DlCO% predicted, mean (SD) | 47.75 (18.63) | 42.07 (21.83) | 0.165 |
| 6-min-walk distance, feet, mean (SD) | 1,114.29 (344.70) | 992.28 (382.86) | 0.125 |
| SGRQ total score, mean (SD) | 35.64 (24.11) | 51.29 (24.32) | 0.002 |
| GOLD stage, n (%) | |||
| 1 | 114 (21.3) | 1 (4.0) | 0.002 |
| 2 | 219 (40.9) | 9 (36.0) | |
| 3 | 89 (16.6) | 2 (8.0) | |
| 4 | 114 (21.3) | 13 (52.0) | |
| Percentage of emphysema, mean (SD) | 17.67 (13.67) | 32.11 (16.29) | <0.001 |
| Perc15, mean (SD) | −945.14 (36.71) | −974.21 (24.00) | 0.004 |
| Average of right and left mainstem wall area percentage, mean (SD) | 44.02 (5.04) | 43.23 (4.46) | 0.611 |
| Average of right and left mainstem wall thickness, mean (SD) | 2.18 (0.32) | 2.09 (0.30) | 0.415 |
Definition of abbreviations: AAT = alpha-1 antitrypsin; COPD = chronic obstructive pulmonary disease; CT = computed tomography; GOLD = Global Initiative for Chronic Obstructive Lung Disease; LTRC = Lung Tissue Research Consortium; MM = PI MM genotype; MZ = PI MZ genotype; Perc15 = CT attenuation at the 15th percentile of the lung CT histogram; SGRQ = St. George’s Respiratory Questionnaire.
The percentage of emphysema is the percentage of lung voxels with CT attenuation ⩽−950 Hounsfield units at inspiratory CT.